Luminescence properties of a new greenish blue emitting phosphor Na5Ca4(PO4)4F:Eu2

• Published in: Journal of alloys and compounds Vol. 534; pp. 97 - 100
• Main Authors: Xiao, Haiyi, Xia, Zhiguo, Liao, Libing, Zhou, Jun, Zhuang, Jiaqing
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 05.09.2012; Elsevier
• Subjects: Alloys; Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diodes; Emission; Emittance; Exact sciences and technology; Excitation; Halophosphate phosphors; Luminescence; Materials science; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Phosphors; Photoluminescence; Physics; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids; Treatment of materials and its effects on microstructure and properties; Ultraviolet; White light; Halophosphate phosphors; Optical properties; Luminescence; Dipole dipole interaction; Photoluminescence; Light emitting diodes; Optoelectronic devices; XRD; Quantum yield; Thermal stability; Quenching; Thermal properties; Ultraviolet radiation; Quantity ratio; Phosphors; Emission spectra; Thermal activation; Solid state reaction; Activation energy; Energy transfer
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.04.042

► Na5Ca4(PO4)4F:Eu2+ phosphors have been studied. ► The emission spectrum showed a single broad band centered at 500nm upon 365nm UV light. ► Na5Ca4(PO4)4F:Eu2+ had a good thermal stability property and high quantum efficiency. A novel greenish blue emitting phosphor, Na5Ca4(PO4)4F:Eu2+, was synthesized by a conventional solid-state reaction, and its phase formation was confirmed by using the X-ray powder diffraction (XRD) technique. The photoluminescence (PL) results showed that the phosphor could be efficiently excited by ultraviolet (UV) light at wavelength of 250–410nm, and it exhibited bright greenish blue emission under 365nm UV light. The emission spectrum showed a single broad band centered at 500nm, corresponding to the 4f65d1→4f7 transition of Eu2+. Eu2+ concentration dependent PL properties in Na5Ca4(PO4)4F:xEu2+ indicated that there was a dipole–dipole interaction of Eu2+ ions. The critical energy-transfer distance was around 19.8Å. Furthermore, this phosphor had good thermal stability and its thermal quenching activation energy was 0.45eV. The measured quantum efficiency of Na5Ca4(PO4)4F:0.01Eu2+ phosphor under 365nm excitation is 76%, which means that the present phosphor is promising in the white light emitting diodes (LEDs) phosphors.